1. Field of the Invention
This invention relates to an image display apparatus such as a television receiver or a display unit for receiving a television signal or a display signal from a computer or the like and displaying an image using a display panel having multiple image-forming devices wired in a matrix.
2. Description of the Related Art
An image display apparatus of related art has n×m image-forming devices (display devices) wired to m row lines and n column lines arranged in the form of a matrix and drives all the devices of a row simultaneously by performing sequential scanning of the row lines and performing modulation in the column direction.
When driving is carried out like this, there is the problem that a voltage drop in the row line arising due to the electrical resistance of the lines causes dispersion in the voltages applied to the image-forming devices.
In this connection, an image display apparatus wherein the pulse widths of driving pulses applied to the image-forming devices are compensated with the purpose of compensating this kind of dispersion of the voltages applied to the image-forming devices is disclosed in Japanese Patent Publication No. 2,759,483.
And, technology relating to an image display apparatus is disclosed in JP-A-8-248,920 (FIG. 22) wherein, in view of the problem that the affect of luminance decrease caused by this kind of voltage drop due to line resistance varies with the inputted image data, the inputted image data is statistically processed, compensation data for compensating the affect is computed, and the image data is combined with compensation data.
However, in the related art mentioned above, because there is no consideration of the fact that the light emission (luminance) characteristics of phosphors (image-forming members) differ from color to color, although the affect of voltage drop is considerably moderated, there has been a need for improvement taking account of the light emission characteristics of the phosphors. Compensation of the light emission characteristic of a phosphor is proposed in JP-A-2000-75,833.
In JP-A-2000-75,833 it is mentioned that the light emission luminance of a phosphor with respect to the strength of an electron beam directed at the phosphor is nonlinear and there is a saturation tendency (hereinafter referred to as nonlinear characteristic, phosphor saturation, phosphor saturation characteristic, etc.). Also, it is mentioned that the phosphor saturation characteristic varies with the type of the phosphor and the beam density and beam duration of the electron beam directed at the phosphor. And it is also mentioned that when the voltage applied to an image-forming device is controlled by means of an ABL (Auto Brightness Limiter) or the like, the light emission characteristic of the phosphor varies with variation in the beam density and duration of the electron beam.
However, even in JP-A-2000-75,833 sufficient examination is not made of voltage drop arising or of any construction incorporating a circuit for compensating this in an image display apparatus which performs gradation conversion of inputted image data corresponding to the light emission characteristics of the phosphors, and further improvement has been needed.
Also, although the present inventors have researched an image display apparatus having processing circuits which both take into account the saturation characteristic of the phosphor and compensate the affects of voltage drop, it was found that when it was made to operate with those in combination, good display of moving pictures was not possible.